1. Field of the Invention
The present invention concerns methods of safely disposing of waste material and systems therefor.
2. Description of the Art
Waste materials and debris are often placed in rolloff boxes, dumpsters, waste carts, railcars, dump trucks and other conventional transportable containers. Waste materials placed in such containers may then be transported to an appropriate site for disposal thereof, typically a landfill, such as a sanitary, industrial or hazardous waste landfill. While these known, transportable containers may be suitable for some types of waste materials, they are unsuitable for many others. For example, hazardous debris may not be safely disposed of by means of these known containers.
More specifically, hazardous debris, which is defined in the Federal Register, Volume 57, No. 180, Aug. 18, 1992, pages 37222-37281 et seq. must be treated by one of a limited list of accepted technologies. Among these technologies are so-called immobilization technologies, which include macroencapsulation, microencapsulation and sealing. Macroencapsulation is described as xe2x80x9capplication of surface coating materials such as polymeric organics (e.g., resins and plastics) or use of a jacket of inert inorganic materials to substantially reduce surface exposure to potential leaching media. Encapsulating material must completely encapsulate debris and be resistant to degradation by the debris and its contaminants and materials into which it may come into contact after placement (leachate, other waste, microbes).xe2x80x9d Id. at 37280.
The use of conventional rolloff boxes, for example, with hazardous debris would not be acceptable because the rolloff boxes do not macroencapsulate or seal the hazardous debris. Yet, the use of conventional transportable waste containers, such as rolloff boxes, is highly desirable from the standpoint of transporting waste material, such as debris, to the eventual disposal site.
The art includes a number of waste container liners, such as U.S. Pat. Nos. 4,385,953; 5,163,555; and 5,110,005. The art also includes references to various transportable containers for cargo and other materials, such as U.S. Pat. Nos. 5,069,352; 4,872,589; 4,722,474; and 4,124,136; and U.K. Patent Specification No. 1,595,227. It is also known to use pieces of high density polyethylene pipe, capped at both ends, to contain hazardous waste materials. Furthermore, it is known to secure hazardous waste materials in metal drums with welded polyethylene encapsulates. However, none of these known techniques and containers adequately addresses the problems presented in safely transporting and disposing of certain waste materials, especially hazardous debris.
Therefore, there is a need in the art for a waste treatment method and a waste treatment system that incorporates the ease of transportation of conventional waste containers combined with secure, safe disposal at a disposal site.
It is an object of the present invention to provide a means for safely encapsulating waste material for appropriate disposal thereof at disposal sites, preferably landfills, most preferably RCRA Subtitle C permitted landfills.
It is an additional object of the present invention to provide a method for encapsulating waste material such that it is substantially isolated from the eventual disposal environment.
It is yet another object of the present invention to provide a method for encapsulating waste material that provides an easy method of transporting the waste material to the appropriate disposal site.
It is a specific object of the present invention to provide a method for encapsulating waste material for the safe disposal thereof in a multistep process. In the first step, a transportable, rigid container, such as a rolloff box or other suitable container, is provided with a liner disposed within the container. The liner is of sufficient rigidity such that the liner is self-supporting when filled with the waste material and/or fill material in the absence of the transportable, rigid container. In a preferred embodiment, the liner is sufficiently rigid such that it can be freestanding with waste material in its interior in the absence of the transportable, rigid container. The liner additionally defines an interior space and an opening, which is adapted to receive the waste material into the interior of the liner.
In the second step of the inventive method, waste material, such as hazardous debris in a preferred embodiment, is placed in the interior of the liner via the opening. As the third step, the waste material is then sealed into or encapsulated within the interior of the liner by the formation of a seal covering the opening, the seal being substantially impermeable to liquid. In this way, the waste material is effectively encapsulated and/or isolated within the sealed liner from the external environment.
This isolation or encapsulation is further achieved by the liner being substantially impermeable to liquids and substantially resistant to chemical degradation. In a preferred embodiment, the resistance to degradation is such that the waste material contained in the liner and the materials with which the liner may come into contact after placement at the disposal site, such as leachate, other waste and microbes, do not adversely affect the substantial impermeability or the substantial structural integrity of the sealed liner. In this way, the waste material encapsulated within the sealed liner may be safely disposed of.
In a preferred embodiment of the present invention, the inventive method additionally includes the step of transporting the container, the liner, and the waste material inside of the liner to the disposal site. In this case, the transporting step may occur before, after or simultaneous with the sealing or encapsulating step. In a most preferred embodiment, the liner would be sealed at the disposal site after transportation of the container to the site has occurred.
In another preferred embodiment, the inventive method may include the additional step of disposing of the sealed liner encapsulating the waste material at the disposal site. In this case, the sealed liner encapsulating the waste material would be separated from the transportable, rigid container and appropriately placed at, for example, the landfill. The rigid, transportable container could then be reused, either for conventional hauling or for reuse in the inventive method.
In another preferred embodiment, the inventive method includes the additional step of filling substantially all of the void spaces in the interior of the liner with fill material before, after or during the placement of the waste material in the liner. When substantially all of the voids are filled, the liner can then be sealed. The fill material further stabilizes the structural integrity of the filled liner for safe disposal.
In another preferred embodiment of the present invention the shape of the liner substantially conforms to the internal shape of the transportable, rigid container. For example, if the transportable container to be used is a rolloff box, the liner would ideally substantially conform to the internal shape of the rolloff box. This provides maximum usage of the internal space of the transportable container, while at the same time minimizing the amount of shifting of the liner within the container that might occur during transport and disposal of the sealed container. However, it is practical to use liners that do not substantially conform to the internal shape of the transportable, rigid container. As but one example of this, a plurality of liners could be placed within a single transportable, rigid container.
In yet another preferred embodiment of the invention, the sealing step is achieved by means of a sealing member. Advantageously, the sealing member substantially conforms to the shape of the opening. The sealing member is then placed in a position relative to the opening such that it substantially covers the opening and a substantially liquid impermeable seal is then formed between the sealing member and the opening. In this way, the waste material within the liner is sealed or encapsulated in the liner from the external environment.
In another aspect of the present invention, a waste encapsulation system is provided for the safe disposal of waste material. This waste encapsulation system includes a transportable, rigid container and a liner disposed within the container. The liner defines an interior space and an opening adapted to receive waste material. The liner is sufficiently rigid such that it is self-supporting when filled with waste and/or fill material in the absence of the transportable, rigid container. The liner is also substantially impermeable to liquids and substantially resistant to chemical degradation. The liner is additionally adapted to form a substantially liquid impermeable seal over the opening. In use, the inventive waste encapsulation system may receive waste material and/or fill material in the interior of the lining via the opening and the waste and/or fill material may then be encapsulated within the sealed liner. The liner and the waste material may be transported in the transportable, rigid container to a disposal site and the sealed liner may be disposed of therein.
Further objects and embodiments of the present invention will be described below.